Preparative procedures of cooling and re-warming increase leukocyte integrin expression and function on neutrophils

The majority of studies involving neutrophil integrin expression and function are performed at physiological temperatures subsequent to routine preparative procedures at 4 degrees C. We have shown that surface expression of the leukocyte integrin molecules on neutrophils is increased by cooling and subsequently re-warming of neutrophils to 37 degrees C when compared with cells held at room temperature or 37 degrees C. This increase in expression is secondary to prior cooling of the neutrophils. There is an associated increase in function of these newly expressed adhesion molecules, making the neutrophils more adherent to endothelium. Preparation of cells at 4 degrees C and subsequently warmed to 37 degrees C is stimulatory for neutrophils, probably causing translocation of intracellular stores of the leukocyte integrins to the cell surface in a manner analogous to the stimulant FMLP. Our results indicate that the cooling of neutrophils during isolation is an inappropriate method of neutrophil preparation.